Production of iron sponge from iron ore according to the dry reduction process



A. SlNDlNG-LARSEN. PRODUCTION OF IRON SPONGE FROM IRON ORE ACCORDING TO THE DRY REDUCTION PROCESS..

APPLICATION FILED APR. 7. 1920.

Patented Oct. 31, 1922..

Patented Qct. 31, 1922.

UNITED STATES PATENT OFFiC.

rnonucrron or men SPONGE rnoivr mom ORE ACCORDING TO THE DRY REDUCTION PROCESS.

Application filed April 7, 1920. Serial No. 372,060.

To all whom it may concern:

Be it known that I, ALF SINDiNG-LARSEN.

a subject of the King of Norway, residing at Vest-re Aker, near Christiania, Norway, have invented certain new and useful Improvements in the Production of Iron Sponge from Iron Ore According to the Dry Reduction Process; and I do hereby declare the following tobe a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to letters or figures of reference marked thereon, which form a part of this specification.

My invention relates to the so called dry reduction process for producing iron sponge directly from iron ore by exposing iron oxid to the action of a gaseous reduction material at a raised temperature.

A process of this kind is described in my U. S. Patent No. 1256939.

My present invention consists in an improved process of this kind and especially relates to the means for carrying away from the reaction chamber the moist gases there formed and utilizing the heat obtained by the condensation of the moisture of such gases to preheat the reduction gases supplied to the reaction chamber.

In the following I shall describe my improved process, reference being had to the accompanying drawings, showing three dif-'" ferent types of reaction apparatus. The invention is not limited to the use of reaction apparatus of these specific constructions the invention comprising the said process without regard to the apparatusused as well as the means for carrying out the same.

Fig.1 is a vertical longitudinal section of reaction apparatus of the horizontal type. Fig. 2 is a longitudinal section of a reaction apparatus of the vertical type and Fig. 3 is a longitudinal section of a reaction apparatus of a simplified form of that shown in Fig. 2. 1

In order/to simplify the description of my invention 1 shall first describe the three different kinds of reaction apparatus shown in the drawings and their mode of operating.

The reaction apparatus shown in Fig. *1

consists of a horizontal retort A, the left hand part of which is divided into two horizontal channels by a wall B. In each of these channels is placed a screw C or I). which rotate in the direction indicated by the arrows. E is the hopper for feeding raw material tothe left end of the upper channel F. 'At the left end of the lower channel G is arranged an outlet for the treated material, which is taken up in a box II. The heat in the reaction chamber is produced by means of an electrical. resistance element 1.

The material entering the left end of the channel F is moved slowly, by means of the screw C, to the right end of the reaction chamber and from here the screw D takes the material over the hottest part of the furnace and carries it to the outlet at the left endof the channel, where it is taken up in the box H.

In the apparatus shown in Fig. 2 the reaction chamber has the form of a'vertical retort A in the axis of which is arranged a tube B within which is a screw C E is the hopper which is placed on the top of a channel F which forms a lateral extension of the tube 13, said channel F being also provided with a feed screw C. Near the bottom of the retort A is placed a feed screw G for conveying the treated material to the box H. The material in the retort is heated by way of electrical resistance elements arranged in the wall of the retort.-

The raw material entering the channel F from the hopper E is fed by means of the screw C in the channel F and the screw C in the tube B, to the top of the retort and is preheated during its movement through the tube B. In the retort the material is heated to the maximum of temperature and exposed to the action of the reduction gases" and the material treated is taken out by way oi the screw G at the bottom of the reaction chamber.

The apparatus shown in Fig. 3 is of the vertical type and differs from the apparatus in Fig. 2'in that the raw material is fed directly to the top of the retort A by means of a screw C in a channel F at the outer end of which the hopper is placed. The apparatus is in other respects like the apparatus shown 7 in Fig; 2.

.-heat, thereupon the pipe carrying the gases I shall now describe the process which forms the subject matter of my invention and which relates to the mannerin which the gases are supplied to and kept in circulation in the apparatus.

The reduction gases which for instance may be hydrogen are for the main-part in-' troduced into the reaction chamber at J and after having passed through the heated material the gases leave the reaction apparatus at K. When the gases leave the reaction chamber their temperature is raised and they have taken up a great amount of'moisture.

My invention consists in the first. place in means whereby the moisture is removed from the gases, this being done in such a manner that the high temperature of the gas when leaving the reaction chamber is utilized to preheat the gases after having been deprived of their moisture before again enteringthe reaction chamber. For this purpose a pipe 0 carrying the gases passes first through a container L in which the gases give off aconsiderable amount of their passes through another container M in which circulates cooling fluid for instance water.

During this passage through the two containers the moist gases give off their moisture and the condensed water is taken up at the/lowest point of the pipe of a vessel N. Just above this latter a pipe P branches off from the pipe Oand this pipe P is connected to a centrifugal pump or blower R and from latter a pipe S leads to the aforesaid con-' tainer L so that the dried gases entering this container are preheated by the tube 0 passing through the same as before described. From the top of this container the pipe T is connected with the inlet opening, or openings J which are so placed that the gas will be introducedat a point intermediate between the point where the raw material is introduced and where the material is taken out of the furnace.

Beside the gas circulating in the above described manner fresh gas has to be supplied to the apparatus and this fresh gas I pre-.

fer to supply at or near the point where the -material leaves the apparatus. The inlet tube for this fresh gas is indicated at X in the drawings. This gas being relatively cold when it enters the apparatus, it will 'be preheated by passing the heated material in" countercurrent. In 'this manner very little heat will be lost, the heat curve obtaining its "the ste gases i done by letting the gases before they again l [enter the furnace pass" throughv a purifier,

- maximum in the middle, sloping towards bothends. I

Athird point in my invention consists in of removing from the circulation e sulphurated hydrogen." This is containing for instance 'e'arth' 'alkali a hydrates, which as is well known takes. up the sulphurof the gas. Thus I am able to treat ores containing considerable sulphur without first submitting them to a roasting process. a

I claim: 1. In the production of iron sponge from iron ore according to the dry reduction process the process which consists in causing pulverulent raw material to be acted uponby a gaseous reducing agent in a heated closed reaction chamber, drawing off the gases, passing them through a condensing apparatus and preheating the dried gases by means I of part of the heat given off by the used gases and then again leading the. so dried and:

heated gases back to the reaction chamber.

2. In the production of iron sponge from iron ore according to the dry reduction process the process which consists in causing .pulverulent raw material to be acted upon by a gaseous reducing agent in a heated closed reaction. chamber, said gaseous re ducing agent being caused to circulate through part of the reaction chamber and through a preheating and condensing apparatus in which the moist and warm gases pass in counter-current with the dried gases.

3. In the production of iron sponge from iron ore according to the dry reduction process a reaction chamber, means to heat the same, means to move the raw material through the heated zone and means to circulate reduction gases through the hot mateof the reaction chamber throughwhich the rawv material isfirst passing and through a pre-heating and condensing apparatusinwhich the moist and warm gases pass in counter-current with the dried gases,.thereby condensing ,condensible products and reheating residual gas and introducing fresh reaction gases into the reaction chamber at or near the point where the treated material isremoved from the apparatus. r

5.. In the production-of iron sponge from iron oreaccording to the dry reduction proc:

ess .a=reaction chamberymeans to heat the" same, means to. move the raw material throughthe heated zone and means to circulate reduct on gases through the hot material and-through a. condensing and heat regenerating apparatus to remove condensible productsfrom' the exit gases and" reheat the residue thereof and through a gas ipurifier,

- gases through the hot material within theadapted to remove from the reduction gases sulphur compounds taken up from the ore.

6. In the production of iron sponge from iron ore according to the dry reduction process a reaction chamber, means to heat the same, means to move the raw material first through the upper part of the chamber and then in opposite direction through the lower part-0f the chamber and means to circulate reduction gases through the hot material within the chamber and through a condensing and regenerating apparatus outside the chamber to condense condensible products and re-heat the residue thereof.

7 In the production of iron sponge from iron ore according to the dry reduction process, a reaction chamber, means to heat the same, means to move the raw material in a substantially vertical direction through the chamber and means to circulate reduction chamber and through a condensing and regenerating apparatus outside the chamber to condense condensible products and reheat the residue thereof.

8. In the production of iron sponge from iron ore according to the dry reduction process, a reaction chamber, means to heat the same, means to move the raw material in a substantially vertical direction through the chamber, first in a upward direction through the central part of the chamber and then in a downward direction and means to circulate reduction gases'through the hot material within the chamber and the exit gases through a condensing and regenerating ap paratus outside the chamber and means to return the pre-heated residual exit gases to said chamber.

In testimony that I claim the foregoing as my invention, I have signed my name in presence of two subscribin witnesses.

ALF SINDI G-LARSEN.

Witnesses:

- ROBERT H, FRAzma,

NATH. A. Fnomrscnon. 

